Sheet feeding apparatus

ABSTRACT

Sheet feeding apparatus incorporating a tray for storing precut sheets; first feeding means contactable with the topmost sheet of the precut sheet stock to feed precut sheets forward in seriatim; means to raise the tray to maintain the topmost sheet of the precut sheet stack in operative contact with the first feeding means as precut sheets are removed therefrom; second feeding means disposed under and jointly movable with the tray and cooperable with the base of the tray to form a passageway for feeding of ready cut sheets from a roll stock converter forward; and aperture means in the tray base enabling the first feeding means to drivingly contact the second feeding means when the tray is empty following raising of the tray to a maximum height.

United States Patent Inventors Donald G. Mallory Lyman H. Turner,Pittsford Appl. No. 782,908 Filed Dec. ll, 1968 Patented May 25, 1971Assignee Xerox Corporation Rochester, N.Y.

SHEET FEEDING APPARATUS 8 Claims, 5 Drawing Figs.

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Int. Cl Field of Search O z Q 7 [56] References Cited UNITED STATESPATENTS 3,393,907 7/1968 Cain 271/39 Primary ExaminerJoseph WegbreitAttorneys-Paul M. Enlow, Norman E. Schrader, James J Ralabate, RonaldZibelli and Frederick E. McMullen ABSTRACT: Sheet feeding apparatusincorporating a tray for storing precut sheets; first feeding meanscontactable with the topmost sheet of the precut sheet stock to feedprecut sheets forward in seriatim; means to raise the tray to maintainthe topmost sheet of the precut sheet stack in operative contact withthe first feeding means as precut sheets are removed therefrom; secondfeeding means disposed under and jointly movable with the tray andcooperable with the base of the tray 271/39, to form a passageway forfeeding of ready cut sheets from a 271/45 roll stock converter forward;and aperture means in the tray B65h 3/06 base enabling the first feedingmeans to drivingly contact the 27 1/39, 9, second feeding means when thetray is empty following raising 28, 62, 45 of the tray to a maximumheight.

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r -/s V ,8 a l 2;; i i; 1 I; s I 29 I3 1 i i =3 0 /2 .457 1 7 I8 74 20 184 3- i 75 7/ 'l i Patented May 25, 1971 3,580,565

5 Sheets-Sheet 1 INVENTORS DONALD G. MALLORY LYMAN H.TURNER A T TORNE)Patented May 25, 1971 5 Sheets-Sheet 2 Patented May 25, 1971 3,580,565

5 Sheets-Sheet 5 Patented May 25, 1971 5 Sheets-Sheet 4 Patented May 25,1971 5 Sheets-Sheet 5 3 Pg S \lbJJl N Nm SIIEET FEEDING APPARATUS Thisinvention relates to a sheet feeding apparatus, and more particularly toa sheet feeding apparatus for feeding both precut sheets and ready cutsheets.

In devices which require a supply of sheets for their operating cycle,for example reproduction or copying machines, there is normally providedeither a precut sheet supply or a roll stock supply with sheets cut tosize by a suitable stock cutter. A suitable transport means for carryingeither the precut sheets or the ready cut sheets from the stock cutterto the user, for example, a reproduction machine is provided. As can beunderstood, individual advantages and disadvantages accrue with botharrangements. For example, a precut sheet system normally entails alower initial cost than the ready cut sheet system which requires astock cutter. However, the material cost is higher for precut sheetsthan for uncut stock. Additionally, the precut sheet system usuallyrequires that various sized sheets be kept on hand to accommodatedifferent demands as well as requiring that the device being served bestopped while the sheet size is changed. On the other hand, a ready cutsheet system avoids or greatly minimizes any storage problem whilepermitting the user to quickly change sheet size without any substantialinterruption in the operating cycle of the device being served.

It is a principal object of the present invention to provide a new andimproved sheet feeding apparatus.

It is a further object of the present invention to provide stock supplymeans adapted to provide both precut and ready cut sheets.

It is an object of the present invention to provide a sheet feedingapparatus incorporating both means to supply precut sheets and ready cutsheets including sheet transporting means, with control means foroperating the sheet supply means to provide selective input of eitherprecut or ready cut sheets to the user.

This invention relates to a sheet feeding apparatus comprising incombination, means adapted to support a supply of first sheets; firsttransport means engageable with the topmost one of the first sheets tofeed the first sheets in seriatim from the apparatus; and secondtransport means adapted to receive a seriatim input of second sheets tosaid apparatus, the second transport means being operatively relatedwith the first sheet support means and cooperable with the first sheetsupport means to feed the second sheets from the apparatus.

Other objects and advantages will be apparent from the ensuingdescription and drawings in which:

FIG. I is a side view partially in section showing the sheet feedingapparatus of the present invention in the precut sheet feeding mode;

FIG. 2 is a top plan view of the sheet feeding apparatus shown in FIG.1;

FIG. 3 is an isometric view showing the drive mechanism for the sheetstock cutter;

FIG. 4 is a side view partially in section showing the sheet feedingapparatus of the present invention in the ready cut sheet feeding mode;

FIG. 5 is a schematic view of the control arrangement for the sheetfeeding apparatus of the present invention.

Referring to the drawings, there is shown the sheet feeding apparatus,designated generally by the numeral 10, of the present invention. Aswill appear, feeding apparatus serves to supply precut sheet stock fromtray 12, or ready cut sheet stock from a roll stock converter or cutter14, to a suitable user. In the exemplary arrangement described, sheetfeeding apparatus 10 supplies copy sheet or paper to a reproduction orcopying machine, such as an electrostatic copier. Other uses andapplications for feed apparatus 10 may be readily contemplated.

In the exemplary arrangement shown, the reproduction machine beingserved has suitable sheet receiving means which may comprise upper andlower guide members 6, 7 respectively through which sheets from feedingapparatus 10 enter. A pinch roll pair 8, 9 may be used to carry thesheets forward into the reproduction machine. Pinch roll pair 8, 9 aredriven by suitable means (not shown).

Sheet feeding apparatus 10 includes a suitable frame 11, which in theexemplary arrangement shown consists of an appendage from thereproduction machine, having spaced outwardly projecting sides 11'.Tracks 19 are suitably secured to the inside wall of each frame side11'. As will appear, tracks 19, which are generally U-shaped in crosssection, support the precut sheet tray 12 for vertical raising andlowering movement.

Referring particularly to FIGS. 1, 2 and 4 of the drawings, tray 12 ofsheet feeding apparatus 10 includes a generally rectangular platelikebase 13 having apertures 18 therethrough adjacent the sheet dischargeend 13 thereof. As will appear, apertures 18 enable feed rollers 40 tocontact idler rollers 67 of ready cut sheet transport 68 wheneverfeeding apparatus 10 is operated in the ready cut sheet feeding mode.

Tray 12 has downwardly projecting sides 20, which serve to support readycut sheet transport 68 therebelow as will appear more fully hereafter.Upwardly projecting supports 22 on sides 20 of tray 12 adjacent the traymidpoint carry upper and lower guide rollers 23, 24. Guide rollers 23,24 are freely rotatable and ride in tracks 19 to support tray 12 forvertical raising and lowering movement. It is understood that thecooperation between the sides of the U-shaped tracks 19 and guiderollers 23, 24 restrain tray 12 against horizontal movement.

The forward edge of sides 20 has gear-teeth 25 thereon. Drive gears 26,which are suitably journaled in frame sides 11, mesh with gear-teeth 25.Intermediate gears 29 are suitably journaled on frame sides 11'. A powershaft 28 is suitably journaled between frame sides 11' and has gears 30in meshing engagement with gears 29. Shaft 28 carries a gear 31 whichmeshes with worm gear 32 on shaft 33 of reversible drive motor 34. As isapparent, motor 34 rotates by means of gears 31, 32 the shaft 28, whichin turn drives gears 30, 29, 26 to raise or lower the tray 12 and thestack 16 of precut sheets thereon. Preferably motor 34 gears 25, 26, 29,30 are chosen to provide incremental raising or lowering of tray 12.

Feed rollers 40 serve to feed the topmost one of the precut sheets ontray 12 between guide members 6, 7 and into the nip of pinch roll pair8, 9. Feed rollers 40 are rotatably journaled on driven shaft 41.Suitable overrunning or one-way clutches 42 are provided to drivinglycouple rollers 40 with shaft 41 on rotation of shaft 41 in the sheetfeeding direction (shown by the solid line arrow in FIG. 1). Clutches 42uncouple rollers 40 from shaft 41 whenever rollers 40 overrun or rotatefaster than shaft 41.

Shaft 41 is pivotally supported from a power shaft 44 by member 45Member 45 has spaced journal arms 46, 47 at the opposite ends thereofwithin which shafts 41, 44 respectively are supported. A driven pulley43 is secured to the portion of shaft 41 between the arms 46 of member45 while a driving pulley 49 is carried by shaft 44 between arms 47 ofmember 45. Drive belt 54 connects pulley 43 with pulley 49. Spring 50biases member 45 in a counterclockwise direction to assure the requisitecontact between feed rollers 40 and the topmost one of the precut sheetson tray 12.

One arm 47' of member 45 comprises a collarlike extension having aradially projecting leg 51 adapted to control tray lift switch 52. Aswill appear, switch 52 cooperates with the feed roller support member 45to maintain feed rollers 40 in continuous driving contact with thetopmost one of the precut sheets on tray 12 as precut sheets are removedtherefrom.

One end of shaft 44 is journaled on frame side 11 by bearing 55. Theother end of shaft 44 is rotatably supported in the opposite side 11' bymeans of clutch member 56. Clutch member 56 includes input shaft 57carrying drive pulley 58. Pulley 58 is connected by belt 59 with asuitable source of power (not shown). Clutch 56, which may beelectromagnetic, serves when engaged to couple shaft 57 with power shaft44 whereby feed rollers 40 are rotated in the sheet feeding directionshown by the solid line arrow in FIG. 1.

During operation, the topmost sheet on tray 12 is frictionally advancedby rollers 40 between guide members 6, 7 and into the nip of pinchroller pair 8, 9. Roller pair 6, 9, which are preferably rotated fasterthan feed rollers 40, carry the sheet forward to the reproductionmachine. The increased velocity imparted to the sheet by roller pair 8,9 is accommodated by one-way clutches 42 which permit rollers 40 tooverrun shaft 41. As will appear, clutch 56 is preferably disengagedfollowing feed of each sheet into the nip of pinch roller pair 8, 9thereby interrupting drive to shaft 41.

Suitable switch means (not shown) is preferably provided to limitdownward movement of tray 12. To control upward movement of tray 12 andassure disposition of ready cut sheet transport 68 in a predeterminedoperating position between cutter 14 and guide members 6, 7, controlswitch 65 is provided. As will appear, switch 65, the operating arm 65'of which is disposed for engagement by projection 21 on one of the sides20 of tray 12 following predetermined raising of tray 12, overrides liftcontrol switch 52 to foreclose operation of motor 34 in a tray raisingdirection.

The ready cut sheet transport 68 includes feed rollers 69 arranged belowapertures 18 in base 13 of tray 12 and opposite feed rollers 40, andabelt type conveyor 70 upstream thereof. Conveyor 70 has one or moreendless belts 73 supported on drive and idler rollers 71, 72respectively. Feed rollers 69, and rollers 71, 72 of conveyor 70 aresuitably journaled in the depending sides 20 of tray 12 such that theperipheral surface of idler rollers 69 and the surface of conveyor belts73 are spaced slightly below the lower surface of tray base 13. As willappear, transport 68 cooperates with the overlaying tray base 13 to forma passage 67 for conducting ready cut sheets from cutter 14 to theslotlilce opening formed by guide members 6, 7. Motor 74, which may besupported from the underside of tray base 13, has output shaft 74'thereof drivingly connected to drive rollers 71 by means of belt 75.Inasmuch as ready cut sheet transport 60 is supported from tray 12,transport 68 moves upwardly and downwardly with tray 12. Raising of tray12 to the predetermined maximum height as determined by control switch65 disposes the ready cut sheet passage 67 in operative alignment withthe outlet of cutter 14 and the opening formed by guide members 6, 7. Atthe same time, feed rollers 40 contact, by means of apertures 18 in traybase 13, feed rollers 69 of transport 68 to form a pinch roll pair forfeeding ready cut sheets forward from the conveyor 70 to guide members6, 7. As will appear, clutch 56 is engaged to drive feed rollers 40during the ready cut sheet operating mode of feeding apparatus 10.

Cutter 14 may comprise any suitable mechanism for cutting sheet stockfrom a roll (not shown) into individual sheets on demand such asdisclosed in copending US. Pat. application Ser. No. 70] ,200 filed Jan.29, 1968 in the name of Lyman H. Turner. The aforesaid stock cutterincludes a metering roll 81 for advancing the desired length of sheetstock forward from the supply roll to a reciprocating knife 02. Cutter14 is arranged such that the discharge therefrom is in operative alignment with the ready cut sheet passage 67 fonned by tray base 13 andconveyor 70 whenever tray 12 is raised to the maximum height asdetermined by switch 65. Accordingly the feed of sheet stock forward bymetering roll 81 brings the leading edge of the sheet stock into passage67 and operative contact with conveyor 70.

Cutter 14 has a feed roll 83 to supply sheet stock from the supply rollto metering roll 81 in accordance with use as sensed by dancer rolltering and feed rolls 81, 83 respectively, is freely movable in verticaltracks 85. The weight of dancer roll 84 on the stock provides requisitestock tensioning. At the same time the height of dancer roll 84 isrepresentative of the length of stock between metering and feed rolls81, 83 respectively.

Drive motor 89 for cutter 14 has shaft 89 thereof connected to feed roll83 through clutch 93 and high speed belt and pulley drive means 95 orthrough clutch 94 and low speed belt and pulley drive means 96. Clutch97 is provided to couple metering roll 91 with motor shaft 89' whileclutch 90 Dancer roll 84, which is between me-' serves to couple knifeoperating means 99 with motor shaft 89.

High and low speed switches 87 and 88 respectively and stop switch 92,which are controlled by dancer roll 84, regulate operation of clutches93, 94 respectively. As will appear, where the supply of stock tometering roll 81 is reduced, dancer roll 84 is raised, operating switch87 to actuate clutch 93 and drive feed roll 83 at high speed. Where thesupply of stock to metering roll 81 increases, dancer roll 84 descends,operating switch 88 to actuate clutch 94 and drive feed roll 83 at lowspeed. Where the length of stock between metering and feed rolls 81, 83respectively becomes excessive, dancer roll 84 descends further,operating stop switch 92 whereby clutch 94 is uncoupled and feed roll 83stopped.

Referring to FIG. 5 of the drawings, to facilitate description, numeral5 is used to designate an exemplary reproduction machine while thedemand or print" signal thereof is designated by the letter A. Suitableselector means is provided to enable feeding apparatus 10 to be operatedin either the precut or ready cut sheet mode. A suitable controllingcircuit 102 regulates operation of feed roll clutch 56 and ofcontrolling circuit 103 in accordance with the setting of selector means100 and the operational demands of reproduction machine 5. Controllingcircuit 103 regulates operation of metering roll clutch 97 in accordancewith control signal inputs from circuit 102, stock length selectorcontrol 105 and upper limit switch 65 as will appear more fully. Lengthselector control 105 additionally regulates operation of knife drivingclutch 98. The selector means 100, when in the ready cut sheet mode,actuates transport drive motor 74, cutter drive motor 89, and feed rollclutch 56 directly.

A suitable timer 107 is provided, timer 107 serving to disengage clutch56 following a preset interval. Suitable controlling circuits 110, 111control operation of tray lift motor 34 in the tray raising direction inaccordance with the condition of raise and limit switches 52, 65respectively while circuit 111 controls operation of cutter feed rollhigh and low speed clutches 93, 94 respectively in accordance with thecondition of high speed, low speed, and stop switches 87, 88, 92respectively. Tray descend control switch 53 serves when actuated toreverse motor 34 and lower tray 12.

As described heretofore, the angular disposition of feed roll supportmember 45 controls tray raise switch 52 to provide automatic raising oftray 12 in accordance with a reduction in the height of precut sheetstack 16 to maintain feed rollers 40 in operative engagement with thetopmost sheet of stack 16. Upper limit switch 65 determines the maximumheight to which tray 12 may be raised. Additionally, switch 65 serves tocondition the cutter control circuit 103 for operation.

For operation of sheet feeding apparatus 10 in the precut sheet mode,selector means 100 is disposed in the solid line position shown in FIG.5 of the drawings to ready controlling circuit 102 for operation. On ademand signal A from reproduction machine 5, circuit 102 actuates clutch56 to couple shaft 57 with power shaft 44 to rotate by means of pulleys43, 49 and belt 54, feed rollers 40. At the same time, circuit 102starts timer 107. Rollers 40, which rotate in the direction shown by thesolid line arrow in FIG. 1, feed the topmost one of the precut sheets intray 12 forward between guide members 6, 7 and into the nip of pinchroll pair 8, 9. Pinch roll pair 8, 9 which preferably rotate in a speedgreater than that of rollers 40, transport the sheet forward withincreased velocity, one-way clutches 42 permitting rollers 40 to overrunshaft 41 and prevent tearing or damage to the sheet.

Following an interval adequate for the sheet to pass into the nip ofpinch rollers 8, 9, timer 107 triggers circuit 102 to disengage clutch56 and terminate drive to feed rollers 40. It is understood that one-wayclutches 42 permit the continued rotation of feed rollers 40 as thesheet is pulled therethrough by pinch roller pair 0, 9.

As the supply of precut sheets is reduced, the level of the precut sheetstack on tray 12 decreases turning support member 45 in acounterclockwise direction about the axis of shaft 44. It is understoodthat spring 50 holds feed rollers 40 in operative contact with thetopmost one of the sheets on tray 12. Following a predetermined decreasein the height of the precut sheet stack 16, leg 51 of member 45 actuatestray lift switch 52 closing contact 52 thereof and triggering circuit110 to operate motor 34 and drive, by means of gears 26, 29, 30, 32,tray 12 upwardly. As tray 12 raises, feed roller support member 45 ispivoted in a clockwise direction about shaft 44 and followingpredetermined upward movement of tray 12, switch contact 52 is closedtriggering circuit 110 to render motor 34 inoperative and stop tray 12.

When the supply of precut sheets on tray 12 is used up, sup-- portmember 45 is in the lowermost position with feed rollers 40 thereof indriving contact with rollers 69 of transport 68 and switch contact 52closed. Tray 12 is accordingly raised upwardly to where projection 21 oftray 12 actuates upper limit switch 65. Switch 65 triggers circuit 110to stop motor 34 terminating further upward movement of tray 12 with theready cut sheet passage 67 operatively disposed between cutter l4 andguide members 6, 7. Switch 65 additionally conditions control circuit103 for operation and may actuate a suitable signal such as a light (notshown) indicating that the supply of precut sheets is exhausted.

Where continued operation in the precut sheet mode is desired, traydescend switch 53 is actuated by the operator, reversing motor 34 andlowering tray 12 to permit precut sheets to be loaded onto tray 12.Preferably, suitable switch means (not shown) are provided to limitdownward movement of tray 12.

For ready cut sheets, selector means 100 is disposed in the dotted lineposition shown in FIG. 5 to operate transport motor 74 and cutter drivemotor 89, and engage clutch 56. It is understood that length selectormeans 105 is set by the operator to provide the desired length of stock.

On a demand signal A, the input from circuit 102 triggers controllingcircuit 103 which actuates clutch 97. Clutch 97 couples motor 89 withmetering roll 81 which feeds sheet stock forward under knife 82 and intothe ready cut sheet passage 67. Following feed of the selected length ofstock to knife 82, a signal from length selector means 105 triggerscircuit 103 to disengage clutch 97 stopping metering roll 81. At thesame time, selector means 105 actuates clutch 98 to couple knifeoperating means 99 with motor 89. Knife 82 severs the stock, the severedstock being carried by sheet transport 70 into the nip of feed and idlerrollers 40, 69 acting as a pinch roll pair.

Transport 70 and pinch roll pair 40, 69 transport the sheet of cut stockforward underneath base 13 of tray 12 and between guide members 6, 7.Pinch roll pair 8, 9 carry the cut sheet forward to the reproductionmachine. The process is repeated in accordance with demand, it beingunderstood that the length of stock provided may be varied throughadjustment of length selector 105.

During operation of cutter 14, the length of stock between metering andfeed rolls 81, 83 respectively may decrease raising dancer roll 84.Following a preset rise, dancer roll 84 actuates switch 87 triggeringcircuit 111 to actuate clutch 93 and couple stock feed roll 83 withmotor 89 through high speed drive means 95. At the same time, clutch 94is disengaged. As the length of stock between metering and feed rolls81, 83 respectively increases, dancer roll 84 descends and following apreset descent, dancer roll 84 actuates switch 88 triggering circuit 111to actuate clutch 94 and couple stock feed roll 83 with motor 89 throughlow speed drive means 96. At the same time, clutch 93 is disengaged.Where the length of stock between feed and metering rolls 81, 83respectively reaches a preset maximum, dancer roll 84 actuates stopswitch 92 to render circuit 111 inoperative whereby low speed clutch 94is disengaged and feed roll 83 stopped.

While the invention has been described with reference to the structuredisclosed herein, it is not confined to the details set forth; but isintended to cover such modifications, or changes as may come within thescope of the following claims.

We claim:

1. In a sheet feeding apparatus, the combination of means including abase section adapted to support a supply of first sheets,

first transport means engageable with the topmost one of said firstsheets to feed said first sheets in seriatim from said apparatus; andsecond transport means adapted to receive a seriatim input of secondsheets to said apparatus, said second transport means being operativelyrelated with said first sheet support means and cooperable with saidfirst sheet support means to feed said second sheets through saidapparatus;

said second transport means being spaced below said base section andcooperable therewith to form a passageway for said second sheets.

2. In a sheet feeding apparatus, the combination of means including abase section adapted to support a supply of first sheets;

first transport means engageable with the topmost one of said firstsheets to feed said first sheets in seriatim from said apparatus;

second transport means adapted to receive a seriatim input of secondsheets to said apparatus, said second transport means being operativelyrelated with said first sheet support means and cooperable with saidfirst sheet support means to feed said second sheets through saidapparatus, said second transport means being spaced below said basesection and cooperable therewith to form a passageway for said secondsheets;

and means for lifting said base section as said first sheets are fedfrom said first sheet supply whereby to maintain the topmost one of saidfirst sheet supply in operative engagement with said first transportmeans.

3. The apparatus according to claim 2 in which said second transportmeans is movable with said base section, said first transport meansbeing arranged to operatively engage said second transport meansfollowing feeding of the last one of said first sheets from said basesection and lifting of said base section with said second transportmeans to a predetermined position whereby said second sheet passagewayis substantially opposite said second sheet input, said first and secondtransport means cooperating to feed said second sheets through saidapparatus.

4. The apparatus according to claim 3 in which said first transportmeans includes at least one driven feed roller, said second transportmeans including an idler roller opposite said first transport means feedroller, said base section including aperture means to enable said firsttransport means roller to drivingly contact said second transport meansidler roller on lifting of said base section to said predeterminedposition; and control means to ready said first and second transportmeans for operation in response to lifting of said base section to saidpredetermined position.

5. In a sheet feeding apparatus, the combination of means adapted tosupport a supply of first sheets, first transport means engageable withthe topmost one of said first sheets to feed said first sheets inseriatim from said apparatus; second transport means adapted to receivea seriatim input of second sheets to said apparatus, said secondtransport means being operatively related with said first sheet supportmeans and cooperable with said first sheet support means to feed saidsecond sheets through said apparatus;

means for driving said second transport means, and control means forreadying said driving means for actuation on feed of the last one ofsaid first sheets from said support means.

6. In a sheet feeding apparatus, the combination of means adapted tosupport a supply of first sheets, first transport means engageable withthe topmost one of said first sheets to feed said first sheets inseriatim from said apparatus;

second transport means adapted to receive a seriatim input of secondsheets to said apparatus, said second transport means being operativelyrelated with said first sheet support means and cooperable with saidfirst sheet support means to feed said second sheets through saidapparatus; said first sheet support means including a tray adapted tohold a stack of said first sheets; said first transport means beingdisposed above said tray whereby to engage the topmost one of said firstsheet stack and feed first sheets from said apparatus; and means forraising said tray in accordance with feed of sheets off said traywhereby to maintain said first sheets in operative engagement with saidfirst transport means. 7. The apparatus according to claim 6 in whichsaid second transport means is disposed underneath said tray andcooperable with the bottom of said tray to form a passageway for

1. In a sheet feeding apparatus, the combination of means including abase section adapted to support a supply of first sheets, firsttransport means engageable with the topmost one of said first sheets tofeed said first sheets in seriatim from said apparatus; and secondtransport means adapted to receive a seriatim input of second sheets tosaid apparatus, said second transport means being operatively relatedwith said first sheet support means and cooperable with said first sheetsupport means to feed said second sheets through said apparatus; saidsecond transport means being spaced below said base section andcooperable therewith to form a passageway for said second sheets.
 2. Ina sheet feeding apparatus, the combination of means including a basesection adapted to support a supply of first sheets; first transportmeans engageable with the topmost one of said first sheets to feed saidfirst sheets in seriatim from said apparatus; second transport meansadapted to receive a seriatim input of second sheets to said apparatus,said second transport means being operatively related with said firstsheet support means and cooperable with said first sheet support meansto feed said second sheets through said apparatus, said second transportmeans being spaced below said base section and cooperable therewith toform a passageway for said second sheets; and means for lifting saidbase section as said first sheets are fed from said first sheEt supplywhereby to maintain the topmost one of said first sheet supply inoperative engagement with said first transport means.
 3. The apparatusaccording to claim 2 in which said second transport means is movablewith said base section, said first transport means being arranged tooperatively engage said second transport means following feeding of thelast one of said first sheets from said base section and lifting of saidbase section with said second transport means to a predeterminedposition whereby said second sheet passageway is substantially oppositesaid second sheet input, said first and second transport meanscooperating to feed said second sheets through said apparatus.
 4. Theapparatus according to claim 3 in which said first transport meansincludes at least one driven feed roller, said second transport meansincluding an idler roller opposite said first transport means feedroller, said base section including aperture means to enable said firsttransport means roller to drivingly contact said second transport meansidler roller on lifting of said base section to said predeterminedposition; and control means to ready said first and second transportmeans for operation in response to lifting of said base section to saidpredetermined position.
 5. In a sheet feeding apparatus, the combinationof means adapted to support a supply of first sheets, first transportmeans engageable with the topmost one of said first sheets to feed saidfirst sheets in seriatim from said apparatus; second transport meansadapted to receive a seriatim input of second sheets to said apparatus,said second transport means being operatively related with said firstsheet support means and cooperable with said first sheet support meansto feed said second sheets through said apparatus; means for drivingsaid second transport means, and control means for readying said drivingmeans for actuation on feed of the last one of said first sheets fromsaid support means.
 6. In a sheet feeding apparatus, the combination ofmeans adapted to support a supply of first sheets, first transport meansengageable with the topmost one of said first sheets to feed said firstsheets in seriatim from said apparatus; second transport means adaptedto receive a seriatim input of second sheets to said apparatus, saidsecond transport means being operatively related with said first sheetsupport means and cooperable with said first sheet support means to feedsaid second sheets through said apparatus; said first sheet supportmeans including a tray adapted to hold a stack of said first sheets;said first transport means being disposed above said tray whereby toengage the topmost one of said first sheet stack and feed first sheetsfrom said apparatus; and means for raising said tray in accordance withfeed of sheets off said tray whereby to maintain said first sheets inoperative engagement with said first transport means.
 7. The apparatusaccording to claim 6 in which said second transport means is disposedunderneath said tray and cooperable with the bottom of said tray to forma passageway for transporting said second sheets from said second sheetinput through said apparatus.
 8. The apparatus according to claim 7 inwhich said second transport means is movable jointly with said tray;said tray raising means being adapted when the supply of said firstsheets is exhausted to raise said tray with said second transport meansso as to operatively position said second sheet passageway substantiallyopposite said second sheet input; said tray bottom having aperture meansenabling said first transport means to operatively contact said secondtransport means and feed said second sheets.